Luminescent Watch Hands With Structured Light Extraction
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Solution Overview
Problem
Existing methods for manufacturing luminescent hands result in poor light distribution and concentration, leading to low luminosity due to light extraction in one plane or reflection inward.
Innovation Solution
A manufacturing method involving a support with a light guide and structured emergent surface, combined with layers of optical materials of varying refractive indices, to enhance light distribution and extraction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If conventional manufacturing methods are used for luminescent hands, then the production process is simple, but the light distribution is poor and luminosity is low
Solution Approach 1:
The patent applies local quality by creating a structured emergent surface with varying local properties. The surface is structured to have different extraction efficiencies at different locations, with the structure designed to optimize light extraction specifically at the emergent surface where light needs to exit the hand. This localized structuring improves luminosity without requiring complete redesign of the entire manufacturing process.
Solution Approach 2:
The patent transitions from conventional planar light extraction to three-dimensional light distribution by creating a structured emergent surface. The structuring adds a new dimension to light extraction by introducing surface relief features that enable light to exit in multiple directions and planes, thereby improving overall light distribution and luminosity beyond what flat surfaces can achieve.
2Illumination intensity
If light guide structures are added to improve light distribution, then luminosity increases, but manufacturing complexity increases
Solution Approach 1:
The patent applies segmentation by dividing the light guide into distinct functional layers with different optical properties. The luminescent hand is segmented into a support layer, luminescent material layer, and structured emergent surface layer. Each segment performs a specific function: the support provides structural integrity, the luminescent material generates light, and the structured surface optimizes light extraction. This segmentation allows for optimized light distribution while managing manufacturing complexity through modular construction.
3Loss of energy
If conventional single-plane light extraction is used, then manufacturing is simple, but light extraction efficiency is low
Solution Approach 1:
The patent addresses light extraction efficiency by transitioning from single-plane to multi-plane extraction through surface structuring. The structured emergent surface creates additional extraction planes and pathways, allowing light to escape from multiple orientations rather than being constrained to a single plane. This dimensional enhancement significantly improves extraction efficiency by reducing total internal reflection and providing multiple escape routes for photons.
Solution Approach 2:
The patent applies parameter changes by modifying the physical parameters of the emergent surface through structuring. The surface is transformed from a smooth plane to a structured surface with specific geometric parameters (ridge height, spacing, patterns) that optimize light extraction. By changing these surface parameters, the patent enhances extraction efficiency without requiring fundamental changes to the light guide material or overall device architecture.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The method enables the production of luminescent hands with improved light distribution and maximum light extraction, achieving enhanced luminosity and decorative effects.
Implementation Method 1
said at least one light guide comprising at least one emergent surface and being configured to guide light
Implementation Method 2
said at least one emergent surface configured to be rough so as to extract light from said at least one light guide
Implementation Method 3
said at least one provision of at least one support comprises a deposition of at least one layer of a first optical material; said at least one layer of a first optical material comprising a first refractive index
Data Source
AI summary
A method for manufacturing a luminescent hand for a horological movement, preferably for a watch. The method includes providing a support comprising a light guide and structuring an emergent surface of the light guide so as to extract a maximum amount of light from the luminescent hand. The luminescent hand includes, over a lower face, a layer of luminescent material including one or more deposit(s) of fluorescent material, opposite a light source. The light source is laced at locations close to the axis of rotation or away from the axis of rotation but at a distance from the luminescent material. Thus, the light source is not placed on the luminescent hand.